Microstructural and mechanical characteristics of Cu-Sn intermetallic compound interconnects formed by TLPB with Cu-Sn nanocomposite
Microstructural and mechanical characteristics of Cu-Sn intermetallic compound interconnects formed by TLPB with Cu-Sn nanocomposite
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DOI：
10.1016/j.mtcomm.2022.104623
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发表时间：
2022-10-11
影响因子：
3.8
通讯作者：
Liu, Changqing
中科院分区：
文献类型：
--
作者：
Jiang, Han;Robertson, Stuart;Liu, Changqing
瞬时液相键合（TLPB）是一种很有前途的三维集成电路（3D IC）技术，但它的速度慢，生产效率低。一种新型的铜锡纳米复合中间层（铜锡NI）由锡基体与嵌入铜纳米线阵列通过电沉积制备可以显着加快键合过程，约20倍。使用Cu-Sn NI的键合时间可以短至约2分钟以实现完整的Cu-Sn金属间化合物（IMC）接头，而在相同的键合条件（250摄氏度）下，使用相同厚度的纯Sn夹层可能需要约60分钟。与通常由Sn夹层形成的柱状Cu 6Sn 5晶粒不同，Cu-Sn NI形成了平均尺寸为-1.6 μ m的细化等轴Cu 6Sn 5晶粒。这种晶粒细化显著地有助于用Cu-Sn NI形成的IMC接头的剪切强度（23.1 +/-3.3MPa）的提高，高于用纯Sn中间层结合的那些（17.9 +/-2.1MPa）。基于实验观察，阐明了新的TLPB工艺的基本机制以及与Cu-Sn Nis键合时形成更精细的显微组织。
Transient liquid phase bonding (TLPB) is a promising technology for three-dimensional integration of circuits (3D IC), but it can be slow and less productive. A novel Cu-Sn nanocomposite interlayer (Cu-Sn NI) composed of Sn matrix with an embedded Cu nanowire array prepared by electrodeposition can significantly accelerate the bonding process, approximately by 20 times. Bonding time with a Cu-Sn NI can be as short as-2 min to achieve a full Cu-Sn intermetallic compound (IMC) joints, whereas it can take-60 min with a pure Sn interlayer of the same thickness under the same bonding conditions (250 degrees C). Unlike the columnar Cu6Sn5 grains commonly formed with Sn interlayer, refined equiaxed Cu6Sn5 grains with an average size of-1.6 mu m are found to be formed with Cu-Sn NI. Such grain refinement has significantly contributed to the improvement of shear strength of IMC joints formed with Cu-Sn NI (23.1 +/- 3.3 MPa), higher than those bonded with pure Sn interlayer (17.9 +/- 2.1 MPa). The underlying mechanisms of the new TLPB process and the formation of finer microstructure when bonding with Cu-Sn NIs are also illuminated and validated based on the experimental observation.